The invention relates to a segment for an annular stator of a dynamo-electric machine. The invention is particularly applicable to very large electrical machines. Generators for wind power installations, tidal power stations, ring motors or drives for construction machines such as mechanical diggers may be mentioned as examples of machines such as these.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that the discussed related art is prior art to the claimed invention.
Energy recovery from regenerative energy sources is becoming evermore important. Correspondingly, the components used for energy conversion are subject to evermore stringent requirements. One consequence of this is that, for example, generators for wind power installations require an ever greater physical volume.
As the rating class rises, wind energy installations without gearboxes are becoming competitive with installations in which a mechanical gearbox is connected between the rotor blades that are driven by the wind and a synchronous generator. The main advantage of a design such as this without a gearbox is that the design is considerably simpler than that of wind power installations with a gearbox. The lack of the gearbox means that fewer rotating machine components are required. This results in less maintenance effort and increased installation availability.
In particular, very large wind power installations generally operate at comparatively low rotation speeds. In an embodiment without a gearbox, installations such as these must therefore be equipped with very large and heavy generators. In this case, the diameter of these machines easily exceeds 4 or 5 m.
As the size of the wind power generators which the higher ratings of these installations necessarily result in become larger, their assembly becomes ever more difficult. Turbines without gearboxes for wind-power or else tidal power stations also result in stringent requirements, however, for transport and logistics.
Generators for wind power installations without gearboxes frequently have an annular rotor with a hollow shaft. One such electrical machine is disclosed, for example, in WO 2006/032969 A2. This document discloses a stator which is subdivided into a plurality of segments in the circumferential apparatus. Each stator segment has a dovetail profile which engages in a window in a stator ring. Each of these sectors can therefore be pulled out in the axial direction without having to remove the entire stator.
It would therefore be desirable and advantageous to provide an improved Winding plan for a segmented stator of a dynamo-electric machine to obviate prior art shortcomings and to make it easier to transport and assemble large electrical machines.